This invention relates generally to signal generators for testing kinescopes and particularly to a circuit for converting a monochrome test signal into individual video color signals for a color display, such as a video monitor.
Among the final stages of manufacturing color kinescopes for video monitors, are the adjustment of the electron beam focusing and convergence. Typically, convergence is a subsequent adjustment but because convergence is affected by focus voltage, focusing must be proper before making any convergence adjustments. Focusing can be facilitated by the use of arbitrary character patterns to cause all three primary colors to be simultaneously displayed on the tube to permit optimizing focusing at all locations on the tube screen. Without an arbitrary test pattern, setting the focus becomes an iterative procedure that is very time consuming. Commercially available test pattern generators do not provide the capability of generating test patterns in all three of the primary colors. However, many commercially available test pattern generators do provide the capability of generating monochrome arbitrary patterns and all necessary synchronization signals. For this reason there is a need for a circuit for transforming the monochromatic test signal into the primary video colors needed for a color video monitor. The present invention fulfills this need.